Mr. Biden's comments are unlikely to be well-received by regime opponents, as they fit a narrative of steadfast US support for a government they want to bring down. About eight protesters and one policeman have died this week as Egypt has sought to bring down the heavy hand of the state against opponents. Since the US provides about $1.3 billion in military aid to Egypt a year, the repressive apparatus of the state is seen by many in Egypt as hand in glove with the US.

Tonight in Cairo, activists said that internet service was being systematically blocked, as was the use of instant messages on local cellphones, despite repeated calls from the US State Department for Egypt to allow social media sites like Facebook and Twitter to remain available to the nation's people. Egypt is bracing for a showdown tomorrow. Organizers have called for massive protests against the regime after noon prayers on Friday, seeking to build on the unprecedented wave of public demonstrations this week calling for an end to Mubarak's rule.

Whether the protests will be as large as democracy activists hope is an open question. Overnight in Egypt, the government was doing everything it could to head them off.

Ahead of a day that could prove decisive, NewsHour host Jim Lehrer asked Biden if the time has "come for President Mubarak of Egypt to go?" Biden answered: "No. I think the time has come for President Mubarak to begin to move in the direction that – to be more responsive to some... of the needs of the people out there."

Asked if he would characterize Mubarak as a dictator Biden responded: “Mubarak has been an ally of ours in a number of things. And he’s been very responsible on, relative to geopolitical interest in the region, the Middle East peace efforts; the actions Egypt has taken relative to normalizing relationship with – with Israel. … I would not refer to him as a dictator.”

He also appeared to make one of the famous Biden gaffes, in comments that could be interpreted as questioning the legitimacy of protesters' demands. Monitor Cairo correspondent Kristen Chick, other reporters in the country, and activists have generally characterized the main calls of demonstrators as focused on freedom, democracy, an end to police torture, and a more committed government effort to address the poverty that aflicts millions of Egyptians.

Biden urged non-violence from both protesters and the government and said: "We’re encouraging the protesters to – as they assemble, do it peacefully. And we’re encouraging the government to act responsibly and – and to try to engage in a discussion as to what the legitimate claims being made are, if they are, and try to work them out." He also said: "I think that what we should continue to do is to encourage reasonable... accommodation and discussion to try to resolve peacefully and amicably the concerns and claims made by those who have taken to the street. And those that are legitimate should be responded to because the economic well-being and the stability of Egypt rests upon that middle class buying into the future of Egypt."

Egypt's protesters, if they're paying attention to Biden at all, will certainly be wondering which of their demands thus far have been illegitimate.